package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.Consumer;
import org.springframework.data.redis.connection.stream.MapRecord;
import org.springframework.data.redis.connection.stream.ReadOffset;
import org.springframework.data.redis.connection.stream.StreamOffset;
import org.springframework.data.redis.connection.stream.StreamReadOptions;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    //静态代码块初始化加载脚本,如果执行的时候才加载太慢了
    static {
        SECKILL_SCRIPT=new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    private static final ExecutorService SECKILL_ORDER_EXECUTOR= Executors.newCachedThreadPool();

    @PostConstruct //当前类初始化完毕以后执行
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable{
        String queueName="stream.orders";
        @Override
        public void run() {
            while(true){
                try {
                    //1.获取消息队列中的订单信息 xreadgroup group g1 c1 count 1 block 2000 streams streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2. 判断消息是否获取成功
                    if(list==null||list.isEmpty()){
                        //如果获取失败说明没有数据，继续下一次循环
                        continue;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    //把map转成order对象
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.消息获取成功，创建订单
                    handlerVoucherOrder(voucherOrder);
                    //5.ACK确认 sack stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    handPendingList();
                }
            }
        }

        private void handPendingList() {
            while(true){
                try {
                    //1.获取消息队列中的订单信息 xreadgroup group g1 c1 count 1 streams stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2. 判断消息是否获取成功
                    if(list==null||list.isEmpty()){
                        //如果获取失败说明pending-list没有数据，结束循环
                        break;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    //把map转成order对象
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.消息获取成功，创建订单
                    handlerVoucherOrder(voucherOrder);
                    //5.ACK确认 sack stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常",e);
                    //为了防止一直失败，所以休眠一会儿
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }
/*    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while(true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();//有元素才会往下走，没有的话会阻塞在这个位置，不会死循环一直执行
                    //2.创建订单
                    handlerVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }

            }
        }
    }*/

    private void handlerVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getVoucherId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁,无参默认为-1，即失败后就不等待
        boolean isLock = lock.tryLock();
        //判断是否获取成功
        if(!isLock){
            //获取失败，返回错误
            log.error("不允许重复下单");
            return;
        }
        try{
            //默认是this调用，也就是目标对象，没有事务功能的，也就是spring事务失效的可能性之一，而proxy才是spring管理的，它的方法才带有事务功能
            proxy.createVoucherOrder(voucherOrder);
        }finally {
            // 释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //2.3 订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.EMPTY_LIST,
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2.判断结果是否为0
        if(result.intValue()!=0){
            //2.1 不为0 , 没有购买资格
            return Result.fail(result.intValue()==1? "库存不足":"不能重复下单");
        }
        //3.获取代理对象
        //获取代理对象（事务）
        proxy= (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }
/*    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.EMPTY_LIST,
                voucherId.toString(),
                userId.toString()
        );
        //2.判断结果是否为0
        if(result.intValue()!=0){
            //2.1 不为0 , 没有购买资格
            return Result.fail(result.intValue()==1? "库存不足":"不能重复下单");
        }
        //2.2 为0, 有个卖资格，把下单信息保存到阻塞队列中
        //6.创建订单
        VoucherOrder voucherOrder=new VoucherOrder();
        //2.3 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4  用户id
        voucherOrder.setUserId(userId);
        //2.5  代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6 放到阻塞队列
        orderTasks.add(voucherOrder);
        //3.获取代理对象
        //获取代理对象（事务）
        proxy= (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }*/

/*    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        //3.判断秒杀是否结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            //已经结束
            return Result.fail("已经结束！");
        }
        //4.判断库存是否充足和用户是否已经买过
        if(voucher.getStock()<1){
            return Result.fail("库存不足！");
        }
        //同步锁实现一人一单
        //synchronized加在类上是是锁this，所有对象共用了一把锁
        //所以应当使用userId，同一个用户使用同一把锁
        //锁应当在事务外面
        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁,五参默认为-1，即失败后就不等待
        boolean isLock = lock.tryLock();
        //判断是否获取成功
        if(!isLock){
            //获取失败，返回错误
            return Result.fail("不允许重复下单");
        }
        try{
            //获取代理对象（事务）
            IVoucherOrderService proxy= (IVoucherOrderService) AopContext.currentProxy();
            //默认是this调用，也就是目标对象，没有事务功能的，也就是spring事务失效的可能性之一，而proxy才是spring管理的，它的方法才带有事务功能
            return proxy.createVoucherOrder(voucherId);
        }finally {
            // 释放锁
            lock.unlock();
        }


//        synchronized (userId.toString().intern()){
//            //获取代理对象（事务）
//            IVoucherOrderService proxy= (IVoucherOrderService) AopContext.currentProxy();
//            //默认是this调用，也就是目标对象，没有事务功能的，也就是spring事务失效的可能性之一，而proxy才是spring管理的，它的方法才带有事务功能
//            return proxy.createVoucherOrder(voucherId);
//        }

    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //直接使用userId this变了锁也就变了
        //使用toString()锁其在常量池中的唯一值，确保userId的值一样时锁就一样
        //4.1 实现一人一单
        int count = query().eq("user_id", userId)
                .eq("voucher_id", voucherOrder.getVoucherId()).count();
        if(count>0){
            //用户已经购买过了
           log.error("用户已经购买过了");
           return;
        }
        //5.扣减库存---(stack作为乐观锁的数据是否更改的标记)
        boolean success = seckillVoucherService.update()
                .setSql("stock=stock-1") //set stock=stock-1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0).update(); //where id=? and stock=?
        if(!success){
            //扣减失败
           log.error("库存不足！");
           return;
        }
        save(voucherOrder);
    }
}
